This invention relates to semiconductor apparatus and, more particularly, to a method of etching semiconductor wafers.
In general, in etching thin, flat semiconductor wafers in order to remove any damaged portions thereof due to sawing and/or lapping a plurality of such wafers is positioned in a cassette, the cassette in turn being mounted on a rotatable support structure submerged in an etchant bath. The support structure and cassette provide appropriate open portions to allow etchant therethrough and into contact with the wafers. The individual wafers are supported adjacent respective edge portions thereof in the cassette, it being therefore understood that portions of the cassette are in quite close proximity to such edge portions. In prior systems, it has been found that even though the cassette and wafers are rotated in the etchant bath, etchant access to and flow around such edge portions is somewhat limited. Thus, it will readily be seen that an uneven etch may sometimes occur. This will clearly be seen to be undesirable, since such etching of semiconductor wafers must be very closely controlled.